Doctors and patients should be given clearer guidance on how to avoid bleeding risks when using Boehringer Ingelheim's new stroke prevention pill Pradaxa, European regulators said on Friday. The European Medicines Agency said data continued to confirm the positive benefit-risk balance of the anticoagulant medicine, despite cases of fatal bleeding, but advice on the risks should be strengthened. Pradaxa is the first in a new class of medicines aimed at replacing the old and problematic drug warfarin. It is designed for use after hip and knee surgery and to prevent strokes in patients with atrial fibrillation, a form of irregular heartbeat common among the elderly.